USPSTF: No Evidence Supports Vitamin D, Calcium for Cancer, Fracture Prevention

ROCKVILLE, Md.The U.S. Preventive Services Task Force (USPSTF) said it can't recommend supplementation with vitamin D or calcium to prevent cancer or bone fractures in its recently released  draft recommendation statement, "Vitamin D and Calcium Supplementation to Prevent Cancer and Osteoporotic Fractures." The task force said evidence doesn't show if taking vitamin D supplements, with or without calcium, to prevent cancer, or taking combined vitamin D and calcium to prevent fractures is safe.

In the draft recommendation, the USPSTF concluded:

Therefore, the USPSTF did not make a recommendation to takeor not to takevitamin D/calcium for cancer and fracture prevention.  However, it recommended against daily supplementation with 400 IU or less of vitamin D3 and 1000 mg or less of calcium carbonate for the primary prevention of fractures in noninstitutionalized postmenopausal women.

Taylor C. Wallace, Ph.D., senior director, scientific and regulatory affairs, the Council for Responsible Nutrition (CRN) said  the draft recommendations does not change expert recommendations for the benefits of calcium. "This weeks draft recommendations by the U.S. Preventive Services Task Force (USPSTF) do a great disservice to Americans, especially postmenopausal women and the elderly, for whom the benefits of calcium and vitamin D have been well established," he said.

He noted long-term Randomized Controlled Trials (RCTs), systematic reviews and meta-analyses show supplementation with calcium and vitamin D is beneficial for bone health, particularly in post-menopausal women and the elderly, when the diet is not sufficient. "For those individuals who are not getting recommended amounts from diet alone, supplementation may be necessary to help prevent falls and fractures."

The National Bone Health Alliance, a subgroup of National Osteoporosis Foundation, said it is important to highlight that this draft recommendation statement does not apply to postmenopausal women or others with osteoporosis, low bone mass, those who have suffered a bone break after the age of 50 or those with other significant risk factors. "These individuals, particularly if they are taking an osteoporosis medication, need to ensure adequate intake of calcium and vitamin D for their medication to be effective," the group said in a press release.

To make its recommendation, USPSTF used two systematic evidence reviews and an updated meta-analysis on vitamin D supplementation with or without calcium.

The USPSTF noted in the largest RCT, the Womens Health Initiative (WHI) study, the vitamin D dose used may have been too low to cause an effect. "There are additional issues in the WHI study," Wallace said. "Of particular concern is the fact that the control group was actually somewhat sufficient in calcium, thereby making it more difficult for the calcium test group to show benefit in comparison."

This draft recommendation statement applies to adults who live at home and not in assisted living or in nursing homes. It does not apply to those who already have had cancer or a broken bone because of osteoporosis.

USPSTF is accepting comments on the draft recommendation until July 10, 2012, at 5:00 p.m. Eastern. Wallace noted CRN looks forward to commenting on the draft recommendations, highlighting its concerns and helping to develop accurate public health recommendations.

USPSTF previously concluded in a separate recommendation that vitamin D supplementation is effective in preventing falls in community-dwelling adults aged 65 years or older who are at increased risk for fall.

"Since falls commonly result in fractures, its common sense for the elderly to consider supplementing with vitamin D and calcium," Wallace noted.

The task force noted research is needed to determine whether daily supplementation with more than 400 IU of vitamin D3 and 1,000 mg of calcium reduces fracture incidence in postmenopausal women or older men. It added that the comparative effectiveness of different preparations of vitamin D (D2 versus D3) or different calcium formations need to be evaluated.

It said prospective studies should also assess the potential benefits of vitamin D and calcium supplementation in early adulthood on fracture incidence later in life. Studies are needed to evaluate the effects of vitamin D supplementation on diverse populations, USPTF said. Because most fracture prevention studies are of white women, who have the highest risk for osteoporotic fractures, it is difficult to extrapolate results to secondary outcomes, such as cancer, in nonwhite populations.

The Institute of Medicine (IOM) and the World Health Organization have set standards for adequate daily intake of calcium and vitamin D as a part of overall health; neither has made specific recommendations for cancer or fracture prevention. IOM recommends 600 IU/d of vitamin D and 1,000 mg/d of calcium for most of the population.